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High Flux Isotope Reactor

Operating at 85 MW, HFIR is the highest flux reactor-based source of neutrons for research in the United States, and it provides one of the highest steady-state neutron fluxes of any research reactor in the world. The thermal and cold neutrons produced by HFIR are used to study physics, chemistry, materials science, engineering, and biology. The intense neutron flux, constant power density, and constant-length fuel cycles are used by more than 500 researchers each year for neutron scattering research into the fundamental properties of condensed matter.

The neutron scattering research facilities at HFIR contain a world-class collection of instruments used for fundamental and applied research on the structure and dynamics of matter. HFIR is also used for medical, industrial, and research isotope production; research on severe neutron damage to materials; and neutron activation analysis to examine trace elements in the environment. Additionally, the building houses a gamma irradiation facility that uses spent fuel assemblies and is capable of providing high gamma doses for studies of the effects of radiation on materials.


The High Flux Isotope Reactor (HFIR) was constructed in the mid-1960s to fulfill a need for the production of transuranic isotopes (i.e., "heavy" elements such as plutonium and curium). Since then its mission has grown to include materials irradiation, neutron activation, and, most recently, neutron scattering. Visit this page to learn more about the history of HFIR.

Reactor Technical Parameters

HFIR is a beryllium-reflected, light-water-cooled and -moderated, flux-trap type reactor that uses highly enriched uranium-235 as the fuel. Visit the following pages to learn more about HFIR's technical parameters:

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